(1) Field of the Invention
The invention relates to a manufacturing method of a printing plate using a liquid photopolymer sachet and an apparatus using the same, and more particularly to a manufacturing method of a printing plate using a liquid photopolymer sachet, which can be freely sealed and freely quantified, to replace a conventional liquid photopolymer sachet, which has been completely sealed and contained the quantified liquid photopolymer.
(2) Description of the Prior Art
At present, the plate making methods of manufacturing a printing plate from a negative film includes a precoating method and a non-precoating method. The precoating method is to use a molded polymer plate, which has the fixed length, width and thickness, as a printing plate body, and a pattern the same as that of the negative film is formed on the polymer plate by way of exposing, washing and other procedures so that the printing plate is manufactured. In the non-precoating method, the molded polymer plate is not used, but a liquid photopolymer is used as an original material. In this method, the liquid photopolymer encloses a range having the fixed length, width and thickness, and then the exposure and harden procedures are performed so that the printing plate is formed after the washing procedure. The typical non-precoating method is performed in conjunction with an exposure machine. In addition, before the molding and exposing procedures are performed, the following steps are necessary. As shown in FIG. 1 in conjunction with the operation guide of the conventional exposure machine, a drawer A1 for exposure of the exposure machine is opened (pulled out). A clamping plate device composed of two pieces of transparent glass A2 and A3 is disposed in the drawer A1, wherein suction channels are typically provided in the sandwich layer of the clamping plate so that air can be sucked at a time simultaneously. Then, the upper glass A2 of the clamping plate is opened, a negative film A4 is placed on the lower glass A3, and supporting columns A5 are disposed at four corners. Next, a covering film A6 is placed on the negative film so that the liquid photopolymer is completely isolated from the negative film to protect it. Then, a close frame A7 is provided around the negative film using a rubber tape as a thickness gauge. Next, a quantified liquid photopolymer is poured into the frame A7. The liquid photopolymer is typically contained in a canned container, the poured quantity of the liquid photopolymer has to be properly controlled, and no bubble is allowed to be formed therein. If a bubble is formed, it must be removed. Thus, a uniform liquid photopolymer layer A8 having the suitable thickness can be formed. Then, a plastic film, such as a polyethelyne polyester, is applied to the surface of the liquid photopolymer layer A8 to serve as a base film A9. The plastic film has to be applied to the liquid photopolymer layer A8 from the middle portion to the outer edges very carefully in order to prevent the bubble from being generated between the base film A9 and the liquid photopolymer layer A8. Next, the upper glass A2 covers the lower glass A3 tightly so that the assembly of FIG. 1 is formed. Then, the drawer A1 is pushed into the exposure machine to perform the exposure procedure, in which a light source A10 illuminates the drawer A1 from the bottom to the top. After the exposure procedure, the printing plate having the base film A9 and the partly hardened photosensitive portion of the liquid photopolymer layer A8 is taken out, and a solvent or water is used to perform the washing procedure so that the printing plate having the base film A9 is formed, as shown in FIG. 2. However, the above-mentioned procedures are very complicated. In particularly, the quantity of the material of the liquid photopolymer layer A8 poured into the frame A7 has to be properly controlled, and the operator has to be very familiar with the technique to prevent the bubble from being generated, or otherwise the molding quality of the printing plate cannot be ensured. In addition, the liquid photopolymer in the opaque portion after the exposure procedure cannot be hardened and can be recycled. However, the liquid photopolymer in the above-mentioned procedure is placed in an open manner and thus cannot be easily collected. So, it is disadvantageous to the recycling operation and the environment protection purpose.
Also, the inventor has disclosed a liquid photopolymer sachet dedicated for the printing and plate making in a non-precoating method in Taiwan Patent Number M259927 in order to solve the drawback of the manufacturing method of the printing plate in the typical non-precoating method. In the M259927 patent, the technical report of the utility patent with the comparison result coded “6” is obtained, wherein a flat transparent sachet body B10 is used, as shown in FIG. 3, and a suitable quantity of liquid photopolymer B20 is contained in the thin sachet body according to the inner size of the thin sachet body. Thus, a closed liquid photopolymer sachet B1 is formed and can be directly placed into the clamping plate and flattened to form a liquid photopolymer structure layer as a printing plate body during the plating making procedure of the non-precoating method. However, the liquid photopolymer sachet B1 is a closed sachet body having the outer sachet body B10 being completely sealed, and the liquid photopolymer B20 contained therein has been completely quantified. That is, the liquid photopolymer sachet B1 is a completely sealed and quantified liquid photopolymer sachet. When the printing plate is to be manufactured, the liquid photopolymer sachet B1 having accurate quantity corresponding to the specifications (i.e., length, width and thickness) has to be selected or provided according to the printing plate so that the plate making procedure can be performed. However, the specification of the printing plate size and the thickness are in variations. Therefore, it is not so easy to prepare an accurate liquid photopolymer sachet B1 having the completely corresponding specifications, or many sachets have to be prepared in stock so that the plate maker may select a proper liquid photopolymer sachet B1. But if a bigger liquid photopolymer sachet B1 is selected, the liquid photopolymer is wasted. This invention is made based on the drawbacks of the conventional liquid photopolymer sachet B1.